A fluorescence-based protocol to monitor bacterial antagonism.

Bacteria are often found in polymicrobial communities where competition for limited space and resources drives antagonistic interactions. Therefore, bacteria have evolved various antibacterial weapons to outcompete their neighbors. These antagonistic interactions can have profound effects on the structure, dynamics, and composition of bacterial communities. To study interactions between two bacterial species, co-culture assays are often employed. The most common approach utilizes selection plates for each bacterial species to quantify recovery after co-incubation. Although this method is relatively accurate and inexpensive, there are some limitations. These assays can be time-consuming, low-throughput, and may present difficulties if the bacteria of interest show similar resistance patterns to one another or if the tolerance to selective agents is unknown. Here, we have developed and validated a method that uses fluorescence as a proxy to screen antibacterial interactions between two species. We utilized two fluorescently tagged bacteria,